The sense of personal control, a central component of the self-concept, has been identified as an important correlate of psychological and physical well-being in later life. Individuals vary in the degree to which they believe they can influence outcomes and behaviors related to their own aging. This research is concerned with how these individual differences in control beliefs both affect and are affected by the aging process. The long-term aim is to enhance functioning in later life by optimizing beliefs in personal control. The present studies have four major goals: (1) to examine the multidimensional structure of personal control, (2) to examine patterns of age differences in the structure and level of control, (3) to articulate the conceptual boundaries of control by considering convergent and discriminant relations with other aspects of the self-concept, and (4) to examine the links between control beliefs and adaptive behavioral functioning. The proposed research draws primarily on theory and methods from the fields of life-span development and aging, personality, and social psychology (especially social learning theories). Cross-sectional and correlational designs are employed. The proposed multidimensional conceptualization of control includes multiple sources (personal efficacy, chance, powerful others) and levels (generalized and domain-specific). Patterns of age differences are expected to vary across dimensions of control. Control beliefs are expected to vary as a function of sex, educational level, health, and personality traits. The investigation of the links between control and behavioral functioning examines whether those with higher levels of personal efficacy and lower levels of chance and powerful others control demonstrate behaviors and attributes that are considered more adaptive for maintaining well-being in later life. An adaptive behavior checklist will be developed to assess levels of adaptive functioning in the elderly in four domains: (1) intellectual/cognitive, (2) social/interpersonal, (3) physical/health, and (4) personal growth. The findings can be applied toward the promotion of optimal functioning and well-being in later life.